program Problem4;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var n, k, c: integer;
    i, hn, hk, t, ht: integer;

begin
  hn:=1;
  hk:=1;
  ht:=1;

  Read(n, k);
  Writeln;
  t:=n-k;

  For i:=1 to n do
    hn:=hn*i;
  For i:=1 to k do
    hk:=hk*i;
  For i:=1 to t do
    ht:=ht*i;

  c:=(hn div (hk*ht));
  Writeln(c);
  Readln;
  Readln;
end.
